Question

F2(g) + 2Cl2O(g) = 2FClO2(g) + Cl2(g)

Expt. #                  [F2] (M)                [Cl2O] (M)                                 Initial rate (M/s)

1                            0.05                      0.010                                          5.0 x 10-4

2                             0.05                      0.040                                          2.0 x 10-3

3                             0.10                       0.010                                          1.0 x 10-3

Calculate the order of the reaction, determine the k, determine t 1/2, how long will it take for the reaction to complete 50% if we double all the reactant concentration.

Answer 1

F2(g) + 2Cl2O(g) = 2FClO2(g) + Cl2(g)

Expt. #                  [F2] (M)                [Cl2O] (M)                                 Initial rate (M/s)

1                            0.05                      0.010                                          5.0 x 10-4

2                             0.05                      0.040                                          2.0 x 10-3

3                             0.10                       0.010                                          1.0 x 10-3

Calculate the order of the reaction, determine the k, determine t 1/2, how long will it take for the reaction to complete 50% if we double all the reactant concentration.

Rate law=

Initial Rate=k [F2]^m [Cl2O]^n   m,n=order with respect to F2 and Cl2O respectively

[f2]=initial concentration of F2

[Cl2O]= initial concentration of Cl2Oonstant

K=rate c

5.0*10^-4 =k (0.05)^m (0.010)^n……………….(1)

2.0*10^-3=k (0.05)^m (0.040)^n………………(2)

Divide equation (1) by (2),

5.0*10^-4/2.0*10^-3=(0.010/0.040)^n

2.5*10^-1=(0.25)^n

0.25=(0.25)^n

n=1

Similarly

1.0*10^-3=k (0.10)^m (0.010)^n……………………(3)

Divide equation ,1 by 3

0.5=(0.05/0.10)^m=(0.5)m

m=1

consider any equation say (1) put the value of m,n and compute K,

5.0*10^-4 =k (0.05)^m (0.010)^n

Or, 5.0*10^-4 =k (0.05) (0.010)

K=1 s-1

T1/2=0.693/K=0.693/1 s-1=0.693 s

First order equation

ln Ct/Co=-kt

Ct= concentration of reactant after time t

Co=initial conc of reactant

T=-1/K ln Ct/Co

given

Co’=2Co

Ct’=50% Co=0.5 Co

T=-1/k ln( 0.5 Co/2Co)=-1/K ln 0.25

T=-1/1 S-1 (-1.386)=1.386 s